[Mesorah] Hamotzi lechem min ha'adama???

[Sholom Simon]

> >>>>>
>My apologies if I am saying something that has already been said 
>and/or is trivial, but it seems to me that there is an obvious 
>difference.  Vegetables can be eaten as they are (or with minimal 
>preparation), whereas bread does not grow from the ground.  Hashem 
>"brings forth bread" in the sense that He provides the raw 
>ingredients, but those ingredients require a great deal of 
>processing before bread is produced.  One might translate "hamotzi 
>lechem" as "He is the ultimate Cause of bread."

I think that is an answer to the "hamotzie" part -- but the original 
question is: why davka "ha'aretz" as opposed to "ha'adamah" ?  (And, 
for p'ri ha'adamah, why that rather than p'ri ha'aretz)?